1. Field of the Invention
This invention relates, in general, to conveyors and, more specifically, to automatic conveyor lubrication apparatus.
2. Description of the Prior Art
A common method of moving parts or components along a manufacturing assembly line is by means of overhead conveyors. Such conveyors are formed of a number of wheeled trolleys which ride along a guideway or track in a continuous closed loop. The trolleys are interconnected by a chain formed of a number of connected links. The parts or components are suspended from the trolley.
The conveyor chain and wheeled trolleys include many interconnected parts which require periodic lubrication. These parts include the trolley roller bearings and the joined parts of the numerous chain links. Automated lubrication equipment has been devised to eliminate the need for manual lubrication and to provide a consistently precise quantity of lubricant to the various portions of the conveyor so as to prevent wear and the problems associated with overlubrication.
Such automated conveyor lubrication systems include a central pump-driven lubrication tank which provides lubricant under pressure throughout flow lines. Control valves or other fluid flow metering devices are energized at the appropriate time to dispense a predetermined quantity of lubricant to the desired element of the conveyor. Typically, switches, such as photo, limit or proximity switches, detect each chain link or trolley of the conveyor as it arrives at the lubrication station and are operative through electric control equipment to energize the valves for the application of lubricant to the conveyor parts.
Since conveyors typically move at a slow rate of speed along a predetermined path within a manufacturing plant, it is oftentimes unnecessary to lubricate the parts or elements of the conveyor on each cycle as this could result in overlubrication which is costly and could cause excess lubricant to drip from the conveyor onto the parts suspended therefrom or the underlying plant area. Thus, counter apparatus as disclosed in U.S. Pat. No. 4,064,970 have been devised to count the number of cycles of the conveyor past the lubrication station and to activate the lubrication apparatus once for each of a predetermined number of cycles of the conveyor. In this manner, all of the desired parts or elements of the conveyor are lubricated once for every predetermined number of cycles of the conveyor past the lubrication station.
However, such previously devised conveyor lubrication apparatus have not been without drawbacks. The counters utilized to provide lubrication once for every predetermined number of cycles of the conveyor past a lubrication station are not easily resetable to provide different frequencies of lubrication. Furthermore, even though the lubrication is applied only once for every predetermined number of cycles of the conveyor past the lubrication station, the central lubricant pump is continually maintained in an energized state in order to maintain pressure within the lubrication lines. This wastes power and places undue wear on the lubrication pump since the lubricant is dispensed only infrequently.
Thus, it would be desirable to provide a conveyor lubrication apparatus which overcomes the problems associated with previously devised conveyor lubrication apparatus. It would also be desirable to provide a conveyor lubrication apparatus which is easily programmable so as to provide any desired frequency of lubrication of the various elements of the conveyor. It would also be desirable to provide a conveyor lubrication apparatus in which the centrally located lubrication pump is de-energized between non lubrication cycles of the conveyor.